Experimental investigation of the residual behaviour of damaged masonry arch structures

L Augusthus-Nelson,G Swift

doi:10.1016/j.istruc.2020.08.008

Abstract

New masonry arch bridges are rarely constructed as part of modern transport networks, however they continue to remain an integral part of modern civil infrastructure due to their overall resilience. This resilience has led to extremely long service lives which in turn has led to the majority of those bridges still in service being either distorted or damaged. Interest in the bridge owners community is directed towards prolonging the service life of these structures rather than replacement with new bridges. The aim of this paper is to explore whether the residual strength and the service life can be reliably established, and whether load limits must be imposed based on condition-based assessment, and/or retrofit the masonry arch system to prolong the life span of these important structures.To investigate residual strength and safe working loads, large scale, soil-backfilled masonry arches were constructed and subsequently subjected to a range of loading scenarios in controlled laboratory environments. Post-failure, these structures were further tested using both cyclic and quasi-static loadings. Results shows that: repeated cyclic loading at safe working load levels do not significantly alter the ultimate load carrying capacity of virgin masonry arch structures; the residual strength of distorted and/or damaged arch structures can be significant; distorted and/or damaged bridges are to some extent able to heal when subjected to repeated cyclic loading at safe working load levels, which is not the case with a virgin arch. Based on these findings, it can be concluded that the safe working load and life span of distorted and/or damaged masonry arch structures must be established in conjunction with the current state of the masonry arch structure.

Highlights

It has long been recognised that masonry arch bridges form an integral component of the transport network in the United Kingdom (UK), with Page et al [23] identifying 40,000 such structures, representing about 40% of the bridge stock
The results suggest that the safe working loads applied to distorted and/or damaged arches significantly enhances the stiffness of the system and ‘heals’ the arch to some extent
The paper reports on a series of laboratory tests on effectively fullscale backfilled masonry arch structures subjected to a wide range of loading conditions

Summary

Introduction

It has long been recognised that masonry arch bridges form an integral component of the transport network in the United Kingdom (UK), with Page et al [23] identifying 40,000 such structures, representing about 40% of the bridge stock. Orban and Gutermann [22] states that more than 60% of the masonry arch structures in use across the European rail network are in excess of 100 years old, with the majority in the UK alone in excess of 120 years old. This is clearly an issue, one that has been recognised for some time, with increasing concerns raised about the reliability of these longlived structures and an awareness of the need for appropriate modelling and assessment methodologies (for example, [19,12])

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